Patient interfaces, such as masks for covering the mouth and/or nose, are used for delivering gas to a subject. Such gases, like air, cleaned air, oxygen, or any modification of the latter, are submitted to the subject via the patient interface in a pressurized or unpressurized way.
For several chronic disorders and diseases, a long-term attachment of such a patient interface to a subject is necessary or at least advisable.
One non-limiting example for such a disease is obstructive sleep apnoea or obstructive sleep apnoea syndrome (OSA). OSA is usually caused by an obstruction of the upper airway. It is characterized by repetitive pauses in breathing during sleep and is usually associated with a reduction in blood oxygen saturation. These pauses in breathing, called apnoeas, typically last 20 to 40 seconds. The obstruction of the upper airway is usually caused by reduced muscle tonus of the body that occurs during sleep. The human airway is composed of walls of soft tissue which can collapse and thereby obstruct breathing during sleep. Tongue tissue moves towards the back of the throat during sleep and thereby blocks the air passages. OSA is therefore commonly accompanied with snoring.
Different invasive and non-invasive treatments for OSA are known. One of the most powerful non-invasive treatments is the usage of Continuous Positive Airway Pressure (CPAP) or Bi-Positive Airway Pressure (BiPAP) in which a patient interface, e.g. a face mask, is attached to a tube and a machine that blows pressurized gas, preferably air, into the patient interface and through the airway in order to keep it open. Positive air pressure is thus provided to a subject through a hose connected to a patient interface or respiratory interface, such as a face mask, that is worn by the subject. The afore-mentioned long-term use of the patient interface is the result, since the wearing of the patient interface takes place during the sleeping time of the subject.
Examples for patient interfaces are:                nasal masks, which fit over the nose and deliver gas through the nasal passages,        oral masks, which fit over the mouth and deliver gas through the mouth,        full face masks, which fit over both, the nose and the mouth, and deliver gas to both,        total face masks, which fit over the whole face, and        nasal pillows, which are regarded as masks as well within the scope of the present invention and which consist of small nasal inserts that deliver the gas directly to the nasal passages.        
The patient interface is usually positioned on the subject's head using some kind of headgear.
The afore-mentioned long term use of the patient interfaces in order to achieve an envisaged therapy result during night often causes discomfort for the patient or a subject. This is due to the afore-mentioned hose connecting the patient interface to an external therapy device which limits the patient in his/her movement freedom and disturbs the sleep of the patient or subject, e.g. by a limited length of the hose or by the hose getting under the patient because of the usual movements during sleep. This therapy device includes a pump device which is controlled based on certain parameters and the therapeutic need. Since the mentioned therapy device is normally disposed stationary beside the bed the subject or patient is permanently connected to this stationary device via the hose during night which causes the afore-mentioned discomfort.
Further, the currently existing therapy devices have a size comparable to two larger books and an according high weight which results in further discomfort if the subject or patient is not staying at the same place for sleeping, e.g. if the subject wants or needs to travel.